The eight-month experiment by Cody Wilson ended with a gun that can be assembled out of plastic parts, and made potentially lethal with the addition of a household nail and a bullet. Video has surfaced of Wilson firing the gun during testing.

Wilson put the plans on the Internet for free, and they were quickly downloaded by more than 100,000 people.

The project was also quickly condemned by politicians. Chuck Schumer, the U.S. senator and gun control advocate from New York, wants plastic guns banned by Congress.

Schumer’s concerns include the theory that the gun could be smuggled past airport security and used on an airplane, and that widespread access to the gun’s blueprints could lead to an explosion of cheap guns.

Schumer pointed to a character played by John Malkovich in the movie In the Line of Fire who builds a plastic and wooden gun in an attempt to assassinate a president.

The debate over plastic guns goes back several decades, including a reference in Die Hard 2 to the alleged ability of the Glock 17, an Austrian-made pistol, to get through scanners because of its ceramic body.

Critics of the 3-D plastic gun were quick to point out several factors. First, a gun made from plastic would have a short shelf life, and it could pose a greater danger to its user than an intended victim because of the construction material.

One deterrent would be the cost of buying a 3-D printer (starting at a $1,000) and the materials needed. (Wilson’s used printer cost $8,000.) Guns are available online, in stores and on the street at much lower prices.

Schumer also expressed a concern about how regulating the publishing of gun-making instructions could have First Amendment considerations.

“Obviously there are First Amendment issues,” Schumer told CNBC, as reported on the Free Republic website. “We’ve had this issue about bombs being put on the Internet in the past. And obviously someone could go overseas and put something on the Internet where our laws don’t govern.”

The issue of homemade guns has been taken up by the courts in the past. In the case of United States v. Stewart in 2003, the U.S. Ninth Circuit Court of Appeals overturned a part of judgment against Robert W. Stewart, Jr., who sold parts kits online to make homemade machine guns. (Stewart was also charged with gun possession from a prior case.)

The Supreme Court decided not to hear the Stewart case, but it told the Ninth Circuit to reconsider it in light of another Supreme Court case, Gonzales v. Raich.

In the Raich case, the court ruled that the Commerce Clause gave Congress to right to ban homegrown marijuana, even when states approved it for medical uses, because of the potential effects on interstate commerce.

In 2006, the Ninth Circuit issued a new ruling in the Stewart case, saying that, “We therefore hold that Congress had a rational basis for concluding that in the aggregate, possession of homemade machine guns could substantially affect interstate commerce in machine guns.”

On Wilson’s website, he says the goal of the project is to “change the way we think about gun control and consumption. How do governments behave if they must one day operate on the assumption that any and every citizen has near instant access to a firearm through the Internet? Let’s find out.”

Wilson’s group is set up as a 501(c)3 non-profit. He doesn’t sell the pistol’s plans, but he does sell plastic gun parts unrelated to the pistol as part of his fundraising efforts. He also accepts online donations and has ads from online parts sellers.

For now, the debate over Wilson’s gun will probably center on its legality under current regulations. The plans require a six ounce piece of metal as part of the pistol, to meet requirements under the Undetectable Firearms Act.

At the time, Wilson told reporters he thought his project was legal and he talked to the Bureau of Alcohol, Tobacco, Firearms and Explosives, which told him the idea of a plastic gun was in a regulatory “grey area.”

The AP reported that Wilson had obtained a manufacture’s license from the ATF before making his pistol.